1. The Belgian Research Initiative on eXotic nuclei (BriX)
Piet Van Duppen
Instituut voor Kern- en Stralingsfysica - K.U.Leuven Belgium
Introduction
Nuclear physics research in Belgium
Research funding
The “Interuniversity Attraction Poles Program”: historical note
The BriX network
“Advanced Research on Exotic Nuclei for Nuclear Physics and
Nuclear Astrophysics”
Research highlights (experimental part, theory discussed by J.-M. Sparenberg)
Conclusion and Outlook

2. Nuclear physics research in Belgium
Federal laboratory

3. Nuclear physics research in Belgium: funding
Fundamental nuclear physics research funding:
Federal: “Interuniversity Attraction Poles Program”
Regional:
Universities:
EU:

4. Exotic Nuclei Nuclear Astrophysics Nuclear Structure
Interuniversity Attraction Poles Program
Period
Partners
Research Activities
U.C.L. – U.L.B. – K.U.Leuven
U.C.L. – U.L.B. – U.Gent - K.U.Leuven
U.L.B. – U.Gent – SCK•CEN -K.U.Leuven
Radioactive beam production
6He, 10,11C, 15O, 18F, 18,19Ne
- Resonant laser ionization of exotic nuclei
- New instrumentation
Laser ion source
LEDA array (segmented silicon detector)
MINIBALL (segmented germanium detector array)
Penning trap for weak interaction studies
Nuclear astrophysics: exp. and theory (e.g. 13N(p,g))
Nuclear structure and reactions: experiment
ground-state properties (moments, charge radii)
decay studies
Coulomb excitation
fusion, fission and transfer reactions
Nuclear structure and reactions: theory
Cluster models, few-body approaches, shell-model, mean-field, symmetry based approaches
Fundamental interaction studies
Nuclear Structure
Nuclear Astrophysics
Exotic Nuclei

5. The Belgian Research Initiative on eXotic nuclei (BriX) (2007-2011)
Belgian partners:
P. Descouvemont, D. Baye, P.-H. Heenen, J.-M. Sparenberg
K. Heyde, C. Wagemans
H. Aït Abderrahim, P. Baeten, P. Schuurmans
M. Huyse, G. Neyens, N. Severijns, R. Raabe, P. Van Duppen
International partners:
GSI (Germany)
GANIL (France)
CSNSM (France)
U.Köln (Germany)

6. The Belgian Research Initiative on eXotic nuclei (BriX) (2007-2011)
Facilities
Species: from neutron beams to radioactive ion beams
Energy: from ~ rest up to 50 MeV/u
Half-life: from ms to hours
KVI-Groningen
CRC-Louvain-la-Neuve
GANIL-Caen
GSI-Darmstadt
ISOLDE - CERN
ILL- Grenoble

7. The Belgian Research Initiative on eXotic nuclei (BriX) (2007-2011)
Physics
n-induced and beta-delayed fission
N=82
Z=82
Shape coexistence along Z=82
N=40
N=50
Nuclear structure along the N=Z line
Z=50
Fundamental interaction studies Z
Z=28
Towards 78Ni: shell structure along Z=28 and N=50 N
“Island of inversion around 32Mg”
Feasibility study for
Structure of light exotic nuclei 20

8. Ar/He from gas purifier
Louvain-la-Neuve Radioactive Beam Facility
CYCLONE110 cyclotron
p,d,a and heavy ions
Radioactive Ion Beams
LISOL gas cell
LISOL - Leuven Isotope Separator On-Line
Laser beams
Target
Cyclotron beam
Exit hole
Sextupole Ion Guide
Ar/He from gas purifier
Filament
Detection
Laser ion source
Laser System
Laser ion source
Thermalisation in a buffer gas cell (500 mbar Ar)
Resonant laser ionization: Z-selection (isomer)
Mass separation: A/Q selection
[M. Facina,- NIMB 226 (2004) 401]
[Y. Kudryavtsev,- NIMB 204 (2003) 336]

9. Wide spectrum of pure radioactive ion beams
Energy: from ~ rest up to 3 MeV/u
Post accelerated beams:
8,9,11Li, 10-12Be, 10C, 17F,
24-29Na, 28-32Mg, 61,62Mn,
61Fe, 68Ni, ,73Cu,
74,76,78,80Zn, 70Se, 88,92Kr,
96Sr, 108In,106,108,110Sn,
122,124,126Cd,138,140,142,144Xe, 140,142,148Ba,148Pm, 153Sm,
156Eu, 182,184,186,188Hg, 202,204Rn
F. Ames et al., Nucl. Instrum. Methods A 538, 17 (2005)
F. Wenander et al., Nucl. Phys. A701, 528 (2002)
O. Kester et al., Nucl. Instrum. Methods B 204, 20 (2003)

10. Double sided Si strip detector
The MINIBALL detector array
Miniball
120Sn
REX-
ISOLDE
PPAC
Beam
monitor
CD – detector
Double sided Si strip detector
(2.3 mg/cm2)
Coulomb excitation
Si barrel detector
Miniball
Transfer reactions
München, Köln, Heidelberg, Darmstadt, Leuven, York, Liverpool, Daresbury, Strasbourg,...
J. Eberth et al., Prog. Part. Nucl. Phys. 46, 389 (2001)

11. Structure of light exotic nuclei: properties of key states
9He
unbound
10He
9Li
179 ms
10Li
12Be
23.6 ms 9B
10B
11B
12B
20.20 ms
12Li 9C
125 ms
10C
19.3 s
11C
20.4 m
11Li
8.5 ms
9Be
10Be y
11Be
13.8 s
12C
12N
11 ms
11N
12O N Z
Beta-decay studies by implantation in a highly
pixelated Si detector and decay correlations
Calorimetric technique:
full energy measured
low threshold
high efficiency
precise normalisation
Measured: 6He (LLN), 11Li (TRIUMF) (2n-halos) 12N, 12B (KVI) (3-alpha states in 12C) 8B (KVI) (spectrum of solar neutrinos)
11Li: R. Raabe,- PRL 101 (2008)
12N, 12B: S. Hyldegaarda,- PLB submitted
6He: R. Raabe,- PRC submitted
8B: analysis in progress

12. Structure of light exotic nuclei: properties of key states
11Li: deuteron emission - decay of the halo
Theory: U.L.B.
Resonance above (Va) or below threshold (Vb)
Coulomb contribution (VC)
Raabe et al., PRL 101 (2008)

13. “Island of inversion” around 32Mg
Present status of the “Island of inversion”
as deduced from static and dynamic moments measurements

14. “Island of inversion” around 32Mg: moment measurements29 30 31 32 33 34 35 36 37 Al 28 Mg 27 Na 26 Ne 25 F 24 22 20 18 16 P S
Production of Al isotopes at GANIL
 b-NMR on polarized fragment beams
g=1.532(2)
g=1.635(2)
Conclusion:
small (<25-30 %) intruder admixture
in the 33Al ground state.
P. Himpe et al., Phys. Lett. B 643 (2006) 257–262

15. “Island of inversion” around 32Mg: two-neutron transfer reactions
Radioactive beam onto a radioactive target
3H(30Mg,32Mg)1H
MINIBALL germanium detector
Si barrel detector
ISOLDE - IS470: Kathrin Wimmer
Mark Huyse

16. First Ionization Limit
6.0 d
57Cu
199 ms
54Co
55Ni
209 ms
55Co
17 h
57Ni
36 h
58Ni
Z=28
N=28
In-gas-cell laser spectroscopy of 57,59Cu: a sample of spectra
65Cu
63Cu
59Cu
57Cu: 6 ions/s
Frequency [GHz]
Cu+ + e-
First Ionization Limit
cm-1
2 = nm
4P01/2
F=2
cm-1
F=1
1 = nm
2S1/2
F=2
CuI: ground state
F=1

17. In-gas-cell laser spectroscopy of 57,59Cu: results
[K. Minamisono,- PRL 96 (2006) ]

18. Monopole interaction towards 78Ni: Cu (Z=29)
Theory
Experiment
N=40
N=40
N=50
5/2-
3/2-
3/2-
5/2-
g9/2
“monopole interaction” 40
n g9/2
Z=28
p1/2
f5/2
p3/2 28
f7/2
protons
neutrons
S. Franchoo et al., PRL81 (1998) 3100, PRC64 (2001)
N. Smirnova et al., PRC69 (2004)
A. Lisetskiy et al, PRC (2004)
T. Otsuka et al., PRL 85 (2005)

19. Results: the 5/2- states A = 63 65 67 69 71 73
at N=40 (69Cu), the 5/2-1 states undergo a significant loss in collectivity, are of different character
the low B(E2; 5/2-  3/2-) value from N=40 onwards indicates that the 5/2- state is essentially of single-particle character
I. Stefanescu et al., PRL 100, (2008 )
I. Stefanescu et al., PRL 98, (2007)

20. Results: the 1/2- states A = 63 65 67 69 71 73
at N=40 (69Cu), 5/2- states undergoes a significant loss in collectivity, are of different character
the low B(E2; 5/2-  3/2-) value from N=40 onwards indicates that the 5/2- state is essentially of single-particle character
the proposed 1/2- shows an important increase in collectivity beyond N=40;
onset of collectivity related to the filling of the g9/2 neutron state.
I. Stefanescu et al., PRL 100, (2008 )
I. Stefanescu et al., PRL 98, (2007)

21. Energy systematics in the odd-mass Cu isotopes9/ 9/ 9/ 9/
9/2+ ~2500 9/
2500 9/ 7/
2000 7/ 7/ 7/ 7/
1500 ? 7/ 7/
pf7/2:
p(2p-1h) 7/ 1/ 5/ 7/ 1/ 5/ 5/ 1/ 5/ 5/
1000 5/ 5/ 7/ 7/ 7/
pp3/2 2+(A-1Ni)
pp3/2 2+(A-1Ni) 1/
N=40
N=28 1/ 5/
collective 1/2- state
500 1/ 1/ 1/
pf5/2 5/ 1/
140 3/ 3/ 3/ 3/ 3/ 3/ 3/ 3/ 3/ 65 3/

22. Collinear laser spectroscopy on Cu isotopes at ISOLDE
Ground state spins, magnetic moments, quadrupole moments, charge radii
from 61Cu up to 75Cu !
73Cu, I=3/2
75Cu, I=5/2
No hyperfine anomaly
ratio of A-factors = constant
if correct spin used in fit
I=3/2
I=5/2
I=7/2
K.T. Flanagan et al.,

23. 186Pb104 Shape co-existence in the lead region
Mean square charge radii
A.N. Andreyev et al., Nature 405, 430 (2000)
186Pb104
Potential energy surface
Shape staggering
Onset of deformation
H. De Witte et al. PRL 98 (2007)
Theory: U.L.B. – U.Gent

24. Shape co-existence in the lead region studied with Coulomb excitation
Nick Bree, Andrew Petts et al. 0+ 2+ 4+
367
1089
375
534
653
Energy (keV)
Coulomb 3 MeV/u
184Hg (3 MeV/u) + 112Cd
Sign, magnitude of deformation
Strongly-coupled
matrix elements
Band mixing

25. a Bf,i Bf,e Rare charge-particle decay studies: ISOLDE and GSI EC/b+
A.N. Andreyev et al.
Beta delayed fission a
bDF g g g g g g g
Bf,i
Bf,e g g
Spontaneous fission
Fission of 180Hg observed in the beta decay of 180Tl
Unexpected asymmetric mass split
(180Hg (Z=80, N=100) = 2 x 90Zr (Z=40, N=50)
Cold fission, important for the end of the r-process

26. Study of (n,f) cross section measurements
Improve data base for transmutation of minor actinides (e.g. 245Cm)
Ternary fission (e.g. 249Cf):
improve the understanding of the ternary fission process (a, t)
important source of helium and tritium gas production in nuclear reactors
Complementary measurements at different facilities:
thermal neutrons: high flux reactor at ILL and BR1 reactor at SCK•CEN
resonance neutrons at TOF facility at IRMM
GELINA (GEel LINear Accelerator)
IRMM Geel (Belgium)
FWHM increases with increasing fissility parameter Z2/A of the compound nucleus:
FWHM(SF) < FWHM(n,f): 0.3 MeV difference (excitation energy broadens)
C. Wagemans et al., Nucl. Sci. Engn. 160 (2008) 200
S. Vermote et al., Nucl. Phys. A806 (2008) 1

27. WITCH Penning trap at ISOLDE – Search for scalar weak currents
Detect recoiling ions in singles for bn angular correlation
Select ion energies sequentially: retardation potential
First recoil ion spectrum
Preliminary
Retardation potential (V)
124Sn recoils
proof of principle
demonstrated
V.Yu. Kozlov et al., NIM B 266 (2008) 4515
S. Coeck et al., NIM A, 574 (2007) 370
S. Coeck et al., NIM A 572 (2007) 585
V.Yu. Kozlov et al., Hyp. Int. 172 (2006) 15
V.Yu. Kozlov et al., Int. J. Mass Sp. 251 (2006) 159
S. Coeck et al., NIM A 557 (2006)
system currently being upgraded
and being prepared for
measurement with 35Ar in 11/2009

28. corrected ft-value for T = 1/2 mirror transitions :
Test of CVC and new value for Vud from T=1/2 mirror decays
nucleus dependent
nucleus independent
corrected ft-value for
T = 1/2 mirror transitions :
calculated
from experiment
29P
19Ne
21Na
37K
35Ar
0+→0+
neutron
pion
mirrors
New value of |Vud| :
|Vud| = (17)
First consistent test of CVC from a set of nuclear transitions other than super-allowed pure Fermi
O. Naviliat-Cuncic & N. Severijns, Phys. Rev. Lett. 102 (2009)
N. Severijns, I.S. Towner et al., Phys. Rev. C 78 (2008)
N. Severijns et al., Rev. Mod. Phys. 78 (2006) 991

29. Fundamental physics with neutrons at PSI: neutron electric dipole moment (nEDM)
Standaard Model value for dn  e cm
(from observed CP-violation in K- and B-meson decays)
observation of nEDM with larger value would point to
NEW source of CP-violation;
- could explain matter-antimatter asymmetry in the Universe
present limit | dn | < x e cm
( C.A. Baker et al., Phys. Rev. Lett. 97 (2006) )
- several extensions of the Standaard Model predict values for
dn in the range  e cm
- present goal: | dn | < 5 x e cm
( by ~ 2015 ; 4 experiments ) 
S. Roccia et al., Phys. Rev. Lett., submitted
A. Knecht et al., Phys. Rev. Lett. , submitted
K. Kirch et al., NIM A (2009) in print

30. Conclusion
Belgian experimental nuclear physics activities under the BriX network:
Radioactive beam production and use (from rest to 50 MeV/u)
Broad spectrum of instrumentation, tools and techniques:
Lasers, arrays of segmented Ge and Si detectors, Penning traps
Moment and charge radii measurements, decay studies, Coulomb excitation, transfer reactions
Physics:
Nuclear-structure, nuclear reaction and fundamental interaction studies using neutrons and exotic nuclei

31. EURISOL Outlook short and intermediate term ENERGY:
European Separator On-Line
Radioactive Nuclear Beam Facility
ENERGY:
Energy upgrade to 10 MeV/u and lower energy capacity
INTENSITY: ISOLDE proton driver beam intensity upgrade
strongly linked to PS Booster improvements including linac4
QUALITY: ISOLDE radioactive ion beam quality: broader spectrum and
higher quality (purity, emittance, time structure) and isomeric beams
Installation and use of the LISOL gas cell based laser ion source at the focal plane of the S3 project (intense heavy-ion beams, production of pure secondary beams, laser spectrocospy)
Participation in DESIR (laser spectroscopy)

32. ISOL@MYRRHA Outlook long term
Nuclear Physics Research at the MYRRHA accelerator at SCK•CEN
600 MeV, mA, D.C. proton beam (from the initial 2.5 mA for MYRRHA)
Different target materials including uranium (e.g. UC: workhorse targets at present)
Ruggedized target-ion source systems that deliver ~50 keV:
ECR 1+: gaseous elements (noble gases, C, N, O,..))
Surface ion source (hot cavity): alkaline and earth alkaline elements
Laser ion sources
ISOL target
1+ ion source
RF-cooler
1+ low-resolution
separator
1+ high-resolution
experiment
MYRRHA
accelerator
Long beam times (e.g. 12 weeks) for experiments that:
need very high statistics
involve many time consuming systematic measurements
hunt for very weak signals
have an inherent low-detection efficiency
In the field of fundamental interaction studies, nuclear physics, atomic physics, condensed matter research,…
is complementary to other ISOL facilities and will be an integral part of the MYRRHA project (see talk H. Aït Abderrahim)

33. Organization of the joined RNB-ENAM conference in 2011 in Leuven
Outlook 2011
Organization of the joined RNB-ENAM conference in 2011 in Leuven
Everybody is cordially invited.
Thank you for your attention

34. N=50 N=40 78Ni Z=28 Evolution towards 78Ni along N=50
Onset of deformation Z>28
llllllll 28 50 40
llll
llllll n ll
llllllllll
sd-shell
1f7/2
2p1/2
1f5/2
2p3/2
1g9/2 p
78Ni
Coulex (up to 68Ni, 73Cu, 80Zn)
Decay studies
Laser spectroscopy studies
J. Van de Walle et al., PRL 99, (2007)
J. Van de Walle et al., PRC 79, (2009)
I. Stefanescu et al., PRL 100, (2008 )
I. Stefanescu et al., PRL 98, (2007)
N=40
N=50
p1/2
g9/2
f5/2
Z=28

35. Ni,Zn,Ge isotopes N=50 isotones this work E(2+1) [keV] E(2+1) [keV] Ge
B(E2,2+10+1) [W.u.]
B(E2,2+10+1) [W.u.] Zn Ni
Neutron Number
Proton Number

36. Zn isotopes N=50 isotones Shell Model (1) 56Ni core :
M. H. Jensen + monopole adjusted by Nowacki
(ep,en)=(1.9e,0.9e) - (U.Gent - N. Smirnova et al, 2006)
Zn isotopes
N=50 isotones
E(2+1) [keV]
E(2+1) [keV]
B(E2,2+10+1) [W.u.]
B(E2,2+10+1) [W.u.] Zn
Neutron Number
Proton Number